ELECTRICITY/MAGNETISM/ELE

CTRICAL CIRCUITS/

SEMICONDUCTORS

1. Two point charge 10 cm apart

produces a force of 1 x 10^-3 g. If

the charges are of equal

magnitude, what is the charge in

statcoulomb?

9.899 statcoulomb

2. Usually, the charge magnitude of

a test-charge is equal to

q (the charge of electron)

3. Who was the first to introduce the

concept of filed lines?

Michael Faraday

4. When a charge distribution is

symmetric, often we use _____ to

simplify electric field calculations.

Gauss’ Law

5. Determine the magnitude of the

electric field inside a sphere that

encloses a net charge of 2 C.

0 (zero)

6. What is the total electric flux

through the surface of a closed

sphere enclosing a net charge of

2 C?

2.26 x 105 NC-1m

2

7. The potential gradient at a

particular point is numerically

equal to _____ at the point.

Electric intensity

8. To get a higher value of

capacitance in a capacitor the

dielectric must be constructed as

thin as possible

9. What is the reciprocal of

capacitance?

Elastance

10. What is the unit of elastance?

Daraf

11. Law which shows that the force

of attraction or repulsion between

two magnetic poles is inversely

proportional to the square of the

distance between them.

Coulomb’s second law

12. When a magnetic substance is

placed near a magnet it will

become a magnet also, this

phenomenon is known as

magnetic induction

13. The capacity of a substance to

become magnetized, and

expressed as the ratio between

the magnetization produced in a

substance to the magnetizing

force producing it.

Magnetic susceptibility

14. The voltage induced in a

conductor is directly proportional

to the rate of change of flux being

cut.

Faraday’s second law of

electromagnetic induction

15. The voltage or emf induced when

the magnetic field is moving or

changing and a conductor is

stationary.

Statically induced emf

16. Reluctance is analogous to

resistance in electrical circuits

and has a unit of At/Wb, its

reciprocal is

Permeance

17. What magnetic materials that can

be easily magnetized in both

directions? Soft magnetic

materials

18. At what temperature does a

magnetic material loses its

ferromagnetic properties?

Curie temperature

19. According to _____, the algebraic

sum of the rises and drops of the

mmf around a closed loop of a

manetic circuit is equal to zero.

Ampere’s circuital law

20. Gaussmeter measures flux

density using what principle?

Hall effect

21. An electromagnetic switch

consisting of a multiturn coil

wound on a iron core and an

armature.

Electromechanical relay

22. What do you call of an

electromagnet with its core in the

form of a close magnetic ring?

Toroid

23. An electrical device has a

resistance of 10 and is supplied

with a 5 ampere constance

current source. If the device is

rated 100 Vdc, determine its

power consumed.

250 W

24. The power dissipated by a 10

load resistor with a current rating

of 5 amperes is _____ if supplied

with a 20 volt dc potential.

40 W

25. How do you connect cells to form

a battery useful for high-power

applications?

In series-parallel

26. In a mesh, the algebraic sum of

all voltages and voltage drops is

equal to zero.

Kirchhoff’s second law

27. The sum of all currents entering a

junction is equal to the sum of

currents leaving away from the

junctions.

Kirchhoff’s first law

28. If a copper wire has an inferred

absolute zero of -234.5 /Co,

determine its temperature

coefficient of resistance at 25

/oC?

0.00385 /oC

29. A certain Thevenin equivalent

circuit has parameters RTH = 10

and VTH = 20V. If this is

converted to Norton’s equivalent

circuit, RN and IN would be

10 and 2A

30. RN and IN of a Norton’s

equivalent circuit are known to be

100 and 10A, respectively. If a

400 load is connected, it will

have a load current of

2 A

31. A chosen closed path of current

flow in a network. In making this

current path there should be no

node nor elements that are

passed more than once.

Mesh

32. A set of circuit elements that

forms a closed path in a network

over which signal can circulate.

Loop

33. In a network. What do we call a

reference point chosen such that

more branches in a circuit met.

Node

34. A common connection between

circuit elements or conductors

from different branches.

Junction

35. A secondary cell whose active

positive plate consists of nickel

hydroxide, and active negative

plate material is powered iron

oxide mixed with cadmium. Its

typical out-put when fully charged

is VO = 1.2V.

Edison cell

36. The maximum current a cell can

deliver through a 0.01 ohm load

during testing.

Flash current

37. In batteries, the material used to

insulate the positive plates from

negative plates are technically

called

Separator

38. Three resistors, R1 = 60 , R2 =

80 and R3 = 100 are

connected in delta. If the network

is to be transformed into star

what would be the value of the

resistor opposite R2?

25.0

39. When can an ac-voltage,

𝑣 = 240 sin 120𝜋𝑡 reach its first

peak?

240 ms

40. The time taken by an alternating

voltage, 𝑣 = 100 sin 120𝜋𝑡 to

reach 20V for the first time

15.3 ms

41. What is the frequency of an

alternating current, if it reaches

45 degrees within 120ms?

60 Hz

42. What is the average voltage of an

alternating voltage, 𝑣 =

100 sin 120𝜋𝑡?

70.71 V

43. What will be the current equation

in a series RC network if supplied

with 𝑣 = 𝑉𝑚𝑠 sin 120𝜋𝑡 source.

The circuit has a power factor pf

= 0.5? 𝒊 = 𝑰𝒎𝒂𝒙 𝐬𝐢𝐧 𝟏𝟐𝟎𝝅 + 𝟔𝟎

44. The power factor (pf) of a series

LC circuit is

0

45. What will happen when the power

factor of a circuit is increased?

Active power increases

46. The apparent power of a series

RC network is given to be 4000

W. If R = 6 , and XC = 8 ,

calculate the true power of the

network.

2400 W

47. What is the significance of

connecting loads in parallel?

It allows independent

operations of loads

48. If a circuit has an admittance of Y

= 0.2 + j0.6, the circuit is

Capacitive

49. The circuit admittance is Y = 0.2

– j0.6, the circuit is

Inductive

50. What will happen to a parallel ac-

circuit if its line frequency is more

than the resonant frequency?

Becomes capacitive

51. If the line frequency of a parallel

ac-circuit is less than the

resonant frequency, the circuit

behaves as

Reactive

52. Absolutely, when can we say that

the circuit is at resonance?

When the voltage and current

are in-phase

53. Inventor of kaleidoscope, a

Scottish physicist who says that

for any dielectric reflector, the

relationship in which the

refractive index is equal to the

tangent of the polarizing angle.

Brewster, Sir David

54. He invented the light-controlled

valve which allowed lighthouses

to operate automatically and won

him the 1912 Nobel prize in

Physics, Who was this Swedish

industrial engineer?

Dalen, Nils

55. British chemist who invented the

electrical primary cell.

Daniell, John Frederic

56. An English obstetrician who

introduced ultrasound scanning.

He pioneered its use as a means

of scanning the growing fetus

without exposure to x-rays.

Donald, Ian

57. He investigated heat and light,

discovered eddy currents induced

in a copper disc moving in a

magnetic field, invented a

polarizer, and made improvement

in the electric arc. Who was this

French physicist who invented

gyroscope?

Foucault, Jean Bernard Leon

58. The people responsible for the

development of the practical

transformers.

Lucien Gaulard & John Gibbs

59. A German scientist who helped

prove the law of conservation of

energy, invented the

opthalmoscope, constructed a

generalized form of

electrodynamics, and foresaw the

atomic structure of electricity.

Helmholtz, Hermann Ludwig

Ferdinand von

60. Who was this US physicist who

invented the cyclotron which

pioneered the production of

artificial radioisotopes?

Lawrence, Ernest

61. A German physicist who

investigated the photoelectric

effect (light causes metals to emit

electrons) and cathode rays (the

stream of electrodes emitted from

the cathode in a vacuum tube).

Lenard, Phillip

62. British physicist who studied the

emission of electricity from hot

bodies, giving the name

“thermionics” of the subject.

Richardson, Owen

63. An English physicist and chemist

who pioneered research into the

radioactive decay of atoms and

coined the term isotope.

Soddy, Frederick

64. A Japanese physicist who

discovered the subatomic

particles called the meson in

1935.

Yukawa, Hideki

65. Elements that has four valence

electrons are classified as

elemental semiconductor

66. The atomic number of an element

represents the number of

protons or electrons

67. The type of crystal lattice in

silicon and germanium.

Face centered cubic (fcc)

68. What is the total charge at the

nucleus of silicon atom?

14e C

69. Which of the following element

configuration that resembles an

alkali metal?

Filled-shell-plus-one-electron

70. Energy required by a valence

electron before it can move or

transfer towards the conduction

band.

Energy gap

71. The energy gap between the

valence band and conduction

band of a semiconductor is in the

order of

one electron volt (1 ev)

72. Typical range of the resistivity of

a semiconductor.

10 – 104 -cm

73. Chemical bond that is significant

in metals.

Metallic bonding

74. What do you call a

semiconductor that is doped with

both donor and acceptor

impurities?

Compensated semiconductor

75. The resistance of a

semiconductor is known as

bulk resistance

76. Silicon is widely used over

germanium due to its several

advantages, what do you think is

its most significant advantage?

Low leakage current

77. Current flow in a semiconductor

that is due to the applied electric

field.

Drift current

78. The movement of charge carriers

in a semiconductor even without

the application of electric

potential.

Diffusion current

79. Typically, how much energy is

required for a valence electron to

move to the conduction band for

a doped semiconductor?

0.05 eV

80. In energy band diagram of a

doped semiconductor, the donor

level

is near the conduction band

81. The acceptor level in a doped

semiconductor

is near the valence band level

82. What is used in the study of the

behavior of free electrons in a

conducting material?

Fermi-Dirac

83. In statistical mechanics, what

distribution function is best used

in analyzing photons?

Bose-Einstein

84. In quantum statistics, the most

suitable functions to be used in

the molecular analysis of gas is

Maxwell-Boltzmann

85. What do you call the boundary

between the energy filled level

and empty level in a

semiconductor material?

Fermi level

86. Which energy level that has free

electrons?

Below the Fermi level

87. The potential required to remove

a valence electron.

Ionization potential

88. A semiconductor that is classified

as a metalloid or semimetal.

Germanium (Ge)

89. Which statement is not true?

Silicon has an oxidation state

of negative four (-4)

90. Compound semiconductors are

also known as

inter-metallic semiconductors

91. What semiconductor that is

mostly used in devices requiring

the emission absorption of lights?

Compound semiconductor

92. For high-speed integrated circuit,

which semiconductor material

given is best to be used?

Gallium arsenide

93. How much impurity concentration

is needed for a sample of silicon

to change its electrical property

from a poor conductor to a good

conductor?

One part per million

94. The restriction of certain discrete

energy levels in a semiconductor

material can be predicted

generally by using what model?

Bohr model

95. At room temperature, in a perfect

silicon crystal, the equilibrium

concentration of thermally

generated electrons in the

conduction band is about

1.5 x 1010

per cubic cm.

96. What is the basis in operations of

semiconductor photoconductors?

EHP optical generation

97. A silicon sample at equilibrium

has a electron concentration of

1.5 x 1010 /cm3, and is doped

with 1015 donors/cm3. Calculate

the minority-carrier

concentrations.

2.25 x 105/cm3

98. Impurities with energy level or

states close to the band edges

are called

shallow states.

99. When an impurity used in doping

produces a level or state that is

close to the center of the gap, it is

called _____ impurity.

Deep state

100. The mobility of electrons and

holes in a semiconductor are

affected mainly by what

scattering mechanisms?

Impurity and lattice scattering

101. In semiconductors, what

scattering mechanism that has a

the smallest effect?

Crystal imperfection scattering

102. Calculate the total carrier mobility

in a semiconductor if the impurity

scattering L = 0.3 m2/vs.

0.14 m2/vs

103. Semiconductor that has the

highest heat conductivity and

therefore used as a heat sink.

Diamond

104. The semiconductor that is used in

xerography.

Selenium (Se)

105. What semiconductor that is good

for high-temperature

applications?

Silicon carbide (SiC)

106. Among the given semiconductors

below, which has the highest

mobility?

Indium antimonide

107. For an electroluminescent of

green and red lights, which

semiconductor is best?

Gallium phosphide

108. A semiconductor glass is known

as

amorphous semiconductor

109. Typical range of power

dissipation for a semiconductor

be considered as “low power” or

“small signal”.

Less than 1 watt

110. Before an electron can participate

in the conduction of electricity, it

must leave from the valence

band and transfer to the

conduction band. Transferring to

be conduction band involves

energy acquisition by an electron

from external sources and this

energy must be greater than the

energy gap of the material. Which

semiconductor material has the

highest energy gap?

Zinc Sulfide (Zns)

111. Which of the following

semiconductors has the smallest

energy gap?

InSb

112. The ease with which a charge

carrier (electron or hole) moves in

a semiconductor material is

known as mobility. It is

InSb

113. In semiconductor materials,

electrons have a higher value of

mobility than holes, but which

semiconductor material has the

slowest electron-mobility?

AlP

114. What is the average lattice

constant of most semiconductors

materials?

0.5 nm

115. What is formed when an n-type

and p-type semiconductors are

brought together?

Pn junction

ELECTRONICS CIRCUITS

(DIODES & TRANSISTORS)

1. When the diode is supplied with a

forward direction potential but

with a magnitude less than the

threshold voltage of the diode,

still it will not “turn-on” and will

only allow a very small amount of

current to pass. This very small

current is known as

Ans. cut-off current

2. As the operating temperature of a

reverse-biased diode is

increased, its leakage of reverse

saturation current will

Ans. increase exponentially

3. Calculate the new threshold

voltage of a germanium diode

when it operates at 100 ˚C.

Ans. 0.113 V

4. A silicon diode has a reverse

saturation current of 50 nA at

room temperature. If the

operating temperature is raised

by 50 ˚C, what is now the reverse

saturation current?

Ans. 1.66 µA

5. In every increase of 10 ˚C in the

operating temperature of a diode

will cause its reverse saturation

current to

Ans. double

6. The resistance of the diode that

is significant when operating with

a small ac signal.

Ans. dynamic resistance

7. When a diode is used in large ac

voltages, the resistance that is to

be considered is

Ans. average resistance

8. At forward bias condition, what

will happen to the diode

resistance when the applied

voltage is increased?

Ans. will decrease

9. When a diode is reverse biased

the depletion region widens,

since it is in between positively

charge holes and negatively

charge electrons, it will have an

effect of a capacitor, this

capacitance is called what?

Ans. transition capacitance

10. In a semiconductor diode, the

total capacitance, that is the

capacitance between terminals

and electrodes, and the internal

voltage variable capacitance of

the junction is called

Ans. diode capacitance

11. What capacitance is significant

when the diode is forward

biased?

Ans. diffusion capacitance

12. The time taken by the diode to

operate in the reverse condition

from forward conduction.

Ans. reverse recovery time

13. In operating a diode at high-

speed switching circuits, one of

the most important parameters to

be considered is

Ans. reverse recovery time

14. The time required for forward

voltage or current to reach a

specified value after switching the

diode from its reverse-to-forward-

biased state.

Ans. forward recovery time

15. A certain diode has a maximum

power dissipation of 500 mW at

room temperature and a liner

power derating factor of 5.0

mW/˚C. How much power the

diode can handle if operate4d at

50˚C?

Ans. 375 mW

16. Diode whose negative resistance

depends on a specific form of

quantum-mechanical bond

structure of the material.

Ans. Gunn diode

17. A diode that is especially

processed so that its high current

flow takes place when the

junction is reverse-biased. It is a

variation of a tunnel diode.

Ans. backward diode

18. A silicon diode that exhibits a

very high resistance in both

directions up to certain voltage,

beyond which the unit switches to

a low-resistance conducting

state. It can be viewed as two

zener diodes connected back-to-

back in series.

Ans. thyrector

19. A type of Reade diode that uses

a heavily doped n-typed material

as its drift region.

Ans. IMPATT diode

20. A device containing more than

one diode. An example is the

full-wave bridge-rectifier

integrated circuit.

Ans. diode pack

21. Is the combination of the

inductance of the leads and

electrodes capacitance of the

junction and the resistance f the

junction of a semiconductor diode

Ans. diode impedance

22. The appearance of RF current

oscillations in a dc-biased slab of

n-type gallium arsenide in a 3.3

kV electric field.

Ans. Gunn effect

23. The device that is formed when

an n-type and p-type

semiconductors are brought

together.

Ans. junction diode

24. When the diode is supplied with a

forward direction potential but

with a magnitude less than the

threshold voltage of the diode,

still it will not “turn-on” and will

only allow a very small amount of

current of pass. This very small

current is known as

Ans. cut-off current

25. As the operating temperature of a

reverse-biased diode is

increased, its leakage or reverse

saturation current will

Ans. increase exponentially

26. Calculate the new threshold

voltage of a germanium diode

when it operates at 100 ˚C.

Ans. 0.113 V

27. A silicon diode has a reverse

saturation current of 50 nA at

room temperature. If the

operating temperature is raised

by 50 ˚C, what is now the reverse

saturation current?

Ans. 1.66 µA

28. In every increase of 10 ˚C in the

operating temperature of a diode

will cause its reverse saturation

current to

Ans. double

29. The resistance of the diode that

is significant when operating a

small ac signal.

Ans. dynamic resistance

30. When a diode is used in large ac

voltages, the resistance that is to

be considered is

Ans. average resistance

31. At forward bias condition, what

will happen to the diode

resistance when the applied

voltage is increased?

Ans. will decrease

32. When a diode is reverse biased

the depletion region widens,

since it is in between positively

charge holes and negatively

charge electrons, it will have an

effect of a capacitor, this

capacitance is called what?

Ans. transition capacitance

33. In a semiconductor diode, the

total capacitance, that is the

capacitance between terminals

and electrodes, and the internal

voltage variable capacitance of

the junction is called

Ans. diode capacitance

34. What capacitance is significant

when the diode is forward

biased?

Ans. diffusion capacitance

35. The time taken by the diode to

operate in the reverse condition

from forward conduction.

Ans. reverse recovery time

36. In operating a diode at high-

speed switching circuits, one of

the most important parameters to

be considered is

Ans. reverse recovery time

37. The time required for forward

voltage or current to reach a

specified value after switching the

diode from its reverse-to-forward-

biased state.

Ans. forward recovery time

38. A certain diode has a maximum

power dissipation of 500 mW at

room temperature and a linear

power derating factor of 5.0

mW/˚C. How much power the

diode can handle if operated at

50˚C?

Ans. 375 mW

39. Diode whose negative resistance

depends on a specific form of

quantum-mechanical bond

structure of the material.

Ans. Gunn diode

40. A diode that is especially

processed so that its high current

flow takes place when the

junction is reverse-biased. It is a

variation of a tunnel diode/

Ans. backward diode

41. A silicon diode that exhibits a

very high resistance in both

directions up to certain voltage,

beyond which the unit switches to

a low-resistance conducting

state. It can be viewed as two

zener diodes connected back-to-

back in series.

Ans. thyrector

42. A type of Read diode that uses a

heavily doped n-type material as

its drift region.

Ans. IMPATT diode

43. A device containing more than

one diode. An example is the

full-wave bridge-rectifier

integrated circuit.

Ans. diode pack

44. It is the combination of the

inductance of the leads and

electrodes, capacitance of the

junction, and the resistance of the

junction of a semiconductor

diode.

Ans. diode impedance

45. The appearance of RF current

oscillations in a dc-biased slab of

n-type gallium arsenide in a 3.3

kV electric field.

Ans. Gunn effect

46. A transistor in which the base is

diffused and the emitter is

alloyed. The collector is provided

by the semiconductor substrate

into which alloying and diffusion

are affected.

Ans. alloy-diffused transistor

47. In a semiconductor device, a p-n

junction formed by alloying a

suitable material such as indium

with the semiconductor.

Ans. alloy junction

48. A transistor in which one or both

electrodes are created by

diffusion.

Ans. diffused transistor

49. A diffused transistor in which the

base, emitter, and collector

electrodes are exposed at the

face of the wafer which is

passivated (has an oxide layer

grown on it) to prevent leakage

between surface electrodes.

Ans. diffused planar transistor

50. A bipolar transistor in which the

base region has been diffused in

the semiconductor wafer.

Ans. diffused-base transistor

51. When n and p materials are both

diffused into the semiconductor

wafer to provide emitter and base

junctions, the transistor is called

Ans. diffused-emitter and base

transistor

52. A mesa transistor whose base is

an n-type layer diffused into a p-

type wafer, the p-type wafer

serves as the collector. Its

emitter is a small p-type area

diffused into or alloyed with the n-

layer.

Ans. diffused-mesa transistor

53. A transistor in which the

semiconductor wafer is etched

down in steps so the base and

emitter regions appear as

physical plateaus above the

collector region.

Ans. mesa transistor

54. An alloy-junction bipolar RF

transistor for which the impurity

concentration is graded from high

on the emitter side of the base

wafer to low on the collector side.

This creates an internal drift field

which accelerates current carriers

and raises the upper frequency

limit of the transistor.

Ans. drift-field transistor

55. A transistor in which a thin metal

crystal is overlaid on another

mesa crystal.

Ans. double-diffused epitaxial

mesa transistor

56. In diffused transistors, what do

you call a figure expressing the

ability of material carriers to

diffuse?

Ans. diffusion constant

57. A BJT that is made by first

growing the emitter and collector

regions as a crystal into which

the base region is later diffused

while the crystal is being pulled.

Ans. grown-diffused transistor

58. A junction transistor made by

adding different impurities

successively to a crystal in its

molten state, and then slicing the

resulting npn formations from the

finished crystal.

Ans. grown-junction transistor

59. A transistor having tiny emitter

and collector electrodes that are

formed by alloying a thin film of

impurity material with a collector

and emitter pits facing each other

on opposite surfaces of the

semiconductor wafer

Ans. microalloy transistor

(MAT)

60. A microalloy transistor having a

uniform base region that is

diffused into the wafer before the

emitter and collector electrodes

are produced by alloying

Ans. microalloy-diffused

transistor

61. The process of growing thin oxide

film on the surface of a planar

semiconductor device to protect

the exposed junction(s) from

contamination and shorts.

Ans. passivation

62. A planar epitaxial transistor which

has been passivated to protect

the exposed junctions.

Ans. planar epitaxial

passivated transistor

63. A transistor in which the emitter,

base and collector elements

terminate on the same plane of

the silicon wafer.

Ans. planar transistor

64. Usually, a pnp transistor is made

by means of electrolysis and

electroplating. The emitter and

collector are formed on opposite

sides of a semiconductor wafer

by training two jets of electrolyte

against its opposite surfaces to

etch and then electroplate the

surfaces.

Ans. surface-barrier transistor

65. If the base-emitter junction is

reversed biased and the base-

collector junction is forward

biased, the transistor will be at

what region of operation?

Ans. cut-off region

66. A transistor with β=100 is

connected as common base, was

found to have a leakage current

ICBO = 1 µA. If the said

transistor is configured as

common emitter, what is the

approximate value of its ICEO?

Ans. 100 µA

67. How is the collector cut-off or

reverse saturation current ICBO

related to the emitter cut-off

current IEBO?

Ans. ICBO ≈ IEBO

68. A transistor is said to be

configured as common emitter if

the emitter terminal is

Ans. not used as an input nor

output

69. Hybrid parameter that is usually

neglected in most circuit analysis.

Ans. hr and ho

70. In most transistor input equivalent

circuit it comprises of a resistor

and a

Ans. voltage source

71. The graph of the product of

collector-emitter voltage VCE and

collector current IC in the

transistor output characteristic

curve

Ans. maximum power curve

72. What will happen to the channel

of a JFET as current flows to it?

Ans. skews

73. The voltage across the gate-

source terminal of a FET that

causes drain current ID equals to

zero.

Ans. pinch-off voltage

74. An early version of the field effect

transistor in which limited control

of current carriers near the

surface of a semiconductor bar or

film was obtained by an external

field applied transversely.

Ans. fieldistor

75. What is the insulator used in

most MOS-FET?

Ans. SiO2

76. An n-channel JFET has a drain-

source saturation current IDSS =

10 mA and a gate-source pinch-

off voltage Vp = -4 V. If the

applied reverse gate-source

voltage VGS = 2 V, calculate the

drain current ID.

Ans. 2.5 mA

77. Base from Shockley’s equation of

a JFET, what is the drain current

when the applied voltage VGS is

exactly equal to the pinch-off

voltage VP?

Ans. zero

78. In MOSFET, it is the foundation

upon which the device will be

constructed and is formed from a

silicon base

Ans. substrate

79. The amount of voltage needed at

the gate-source terminal for an

enhancement type MOSFET so

that a channel can be formed for

the current to flow.

Ans. threshold voltage

80. To switch off the depletion type

MOSFER, the channel should be

depleted. Depletion of the

channel is done by applying

enough voltage across the gate-

source terminal. What do you call

this voltage?

Ans. pinch-off voltage

81. In an n-channel enhancement

type MOSFET, the gate voltage

should be ______ with respect to

the source in order to produce or

enhance a channel.

Ans. positive

82. To deplete a channel from a p-

channel IGFET depletion type,

the gate voltage should be

______ with respect to the

source terminal.

Ans. positive

83. A junction field effect transistor

has a drain saturation current of

10 mA and a pinch-off voltage of

-4 V. Calculate the maximum

transconductance.

Ans. 5.0 mS

84. An n-channel MOSFET depletion

type has a drain saturation

current IDSS = 10 mA and a

pinch-off voltage of -4 V.

Calculate the maximum

transconductance of the

transistor.

Ans. 5.0 mS

85. Calculate the transconductance

of a p-channel MOSFET

enhancement type if the gate-

source voltage VGS = -8 V,

threshold voltage VT = -4 and a

constant k = -0.3 mA/V2.

Ans. 2.4 mS

86. What will happen to the

conductivity of the channel of an

enhancement type MOSFER if

the proper gate voltage is

increased?

Ans. decreases

87. The cutoff frequency of a JFET is

dependent on channel length by

a factor of

Ans. 1/L2

88. An n-channel enhancement type

MOSFET has a threshold voltage

of VT = 2.5 V. If the applied gate-

source voltage VGS = 4 V, what

is the approximate drain current

ID?

Ans. 0.675 mA

89. Which FET has a wide and short

effective channel?

Ans. V-MOSFET

90. The load line position is

dependent of

Ans. the load resistance and

the supply voltage

91. What will happen to the

magnitude of the load line slope if

the load resistance is increased?

Ans. decreases

92. One method of stabilizing

transistor circuits is to add an

emitter resistance. This

resistance causes the load line

slope to

Ans. become less negative

93. The power gain that is lost due to

the emitter bias resistor can be

recovered by

Ans. shunting a by-pass

capacitor

94. When a capacitor is involved at

the output circuit of a transistor

amplifier it would mean

Ans. a different dc and ac load

line

95. How does the emitter by-pass

capacitor affect the dc load line?

Ans. it does not affect the dc

load line

96. In analyzing the quiescent

currents and voltages, on what

load line do you refer?

Ans. dc load line

97. The position of the Q-point along

the load line is greatly affected by

what component?

Ans. base-resistor

98. What will happen to the position

of the Q-point if the resistance

base-resistor is increased?

Ans. it moves downward

99. For a fixed-biased transistor

circuit, what will happen to the Q-

point when the operation

temperature rises?

Ans. it moves upward

100. For a battery operated transistor

circuit, where is a good position of

the Q-point in order to minimize

battery consumption?

Ans. near cutoff region

101. When troubleshooting a typical

transistor amplifier in the active

region, VCE is usually _____ the

supply voltage VCC.

Ans. about 25% to 75% of

102. Calculate the stability factor due to

the variation of ICBO from 1 nA to

21 nA when the temperature

changes from room temperature to

100 ˚C. The change in collector-

current due to the change of ICBO

was found to be 0.5 µA.

Ans. 25

103. The higher the stability factor

means, a transistor circuit that is

more sensitive to temperature

Ans. variations, and therefore

undesired

104. What stability factor that gives the

highest value for a typical voltage-

divider bias transistor circuit?

Ans. S (ICO)

105. Calculate the change in the

collector current due to the change

in ICO for a transistor circuit at 100

˚C. ICO at room temperature is

given to be 0.1 nA and increases to

20 nA at 100 ˚C. The circuit has a

stability factor S(ICO) = 25.

Ans. 0.5 µA

106. For most common-emitter

configuration with different methods

of biasing, what is the maximum

stability factor due to the change of

the reverse saturation current ICO?

Ans. β + 1

107. What is the approximate output

impedance of a common-emitter

fixed-bias configuration? The

collector resistance RC is the only

load resistance/

Ans. RC

108. A FET is biased with a voltage-

divider configuration and is set at

the active region. Ideally, what is

the gate current?

Ans. 0 mA

109. What type of FET that can be

biased with both negative and

positive gate-source voltage VGS?

Ans. MOSFET depletion type

110. How do you classify an amplifier

used to amplify either amplitude

modulated (AM) or frequency

modulated (FM) signals?

Ans. class S

111. Which class of amplifiers that have

the highest efficiency?

Ans. class D

112. Transistorized class C power

amplifiers will usually have an

efficiency of

Ans. 33%

113. For pulse-amplification, class D

amplifier is mostly used. How

efficient is a class D amplifier?

Ans. its efficiency reaches over

90%

114. The Q-point of a class D amplifier

can be set or positioned at what

region in the load line?

Ans. any of these

115. What do you call an amplifier that is

biased to class C but modulates

over the same portion of the curve

as if it were biased to class B?

Ans. class BC

116. Two class B amplifiers connected

such that one amplifies the positive

cycle and the other amplifies the

remaining negative cycle. Both

output signals are then coupled by

a transformer to the load.

Ans. transformer-coupled push-

pull amplifier

117. A push-pull amplifier that uses npn

and pnp transistors to amplify the

positive and negative cycles

respectively.

Ans. complementary-symmetry

amplifier

118. A push-pull amplifier that uses

either npn or pnp as its final stage.

The circuit configuration looks like

the complementary-symmetry.

Ans. quasi-complementary push-

pull amplifier

119. Distortion that is due to the inability

of an amplifier to amplify equally

well all the frequencies present at

the input signal/

Ans. amplitude distortion

120. Calculate the second harmonic

distortion for an output signal

having a fundamental amplitude of

3 V and a second harmonic

amplitude of 0.3 V.

Ans. 10 %

121. An amplifier has the following

percent harmonic distortions: D2 =

10%, D3 = 5% and D4 = 1%. What

is the amplifier %THD?

Ans. 11.22%

122. T-equivalent circuit for transistor is

considered as a _____

representation/

Ans. physical

123. What transistor model that uses a

parameter value that is directly

derived from the operating

condition?

Ans. re or dynamic model

124. The transistor model that is best

suited for high frequency

applications/

Ans. Giacolleto model

125. Another name of Giacolleto model

for transistor modeling is

Ans. hybrid-pi model

126. What model is appropriate to use, if

for a given transistor amplifier, beta

(β) is the only parameter available

and we want to solve for its input

and output impedances?

Ans. dynamic model

127. When the transistor is operating at

saturation region, dc-current is best

determined by using what model?

Ans. Ebers-Moll model

128. A two-stage transistor amplifier in

which the output collector of the

first stage provides input to the

emitter of the second stage. The

final output is then taken from the

collector of the second or last

stage.

Ans. cascode configuration

129. Famous transistor amplifier

configuration designed to eliminate

the so called Miller effect.

Ans. cascode amplifier

130. Transistor arrangement that

operates like a darlington but uses

a combination of pnp and npn

transistors instead of both npn.

Ans. feedback pair

OP AMPS/ COMPUTERS

1. Thin-film integrated circuit refers

to film thickness of

approximately 1um.

2. Classifications of ICs according

to functions include linear, digital

and microwave. Which of these

classes greatly relies on hybrid

technology? Microwave ICs

3. The term “monolithic” is derived

from the Greek words monos and

lithos which respectively mean

single and stone (single stone)

4. Devices or components such as

transistors and diodes are mostly

fabricated in ICs by diffusion

5. In most planar ICs, what do you

call the layer that protects the

surface of the chip from external

contaminants? Oxide layer

6. Which comes first in the planar

process of fabricating ICs?

Crystal growth

7. A technique used for obtaining a

relatively large single crystal from

a semiconductor material. the

process consists essentially of

dipping a tiny seed crystal into a

crucible of molten mass of the

same substance and then slowly

withdrawing it while rotating.

Czochralski method.

8. In IC fabrications, the substrate is

usually produced by Czochralski

process.

9. The process used to grow a layer

of single-crystal semiconductor

as an extension of the existing

crystal wafer of the same

material. epitaxial

10. In fabricating ICs using planar

technology, what is the basic

method of adding impurities?

Diffusion

11. The introduction of impurities into

a semiconductor inside a hot

furnace during IC fabrication.

Diffusion

12. A method of introducing

impurities in IC fabrication

wherein the appropriate ions are

carried by an accelerating beam.

Ion-implantation

13. Which method of doping that is

used in producing narrow regions

in an IC? Ion-implantation

14. Type of diffusion in which the

impurity concentration at the

semiconductor surface is

maintained at a constant level

throughout the diffusion cycle.

Constant-source diffusion

15. An alternative method rather than

diffusion in introducing impurities

into a semiconductor wherein the

impurities are made to penetrate

into the wafer by an ion beam.

Ion-implantation.

16. A method of producing integrated

circuit by photographing a pattern

of the circuit on a suitable light-

sensitized surface of semicon-

ductor and chemically etching

away unwanted portions of the

surface. Photolithographic

process.

17. In IC fabrication, the photo-

sensitive emulsion coated at the

wafer surface to be masked is

called photoresist

18. The removal of unmasked Silicon

Dioxide (SiO2)at the wafer

surface in IC fabrication etching

19. The removal of the remaining

photoresist in the wafer after

etching during IC fabrication.

Stripping.

20. Covering or coating on a

semiconductor surface to provide

a masked area for selective

etching or deposition masking

21. In most IC fabrications, how is

the connection pattern between

components defined? By

masking

22. What do you call the process of

interconnecting the components

in an IC during fabrication?

Metallization

23. The conducting material that is

mostly used to interconnect

components on chips during

metallization process. Aluminum

24. Is the process of making the

semiconductor chip or wafer

insensitive to any contaminations

that might cause drift of

parameter or premature failure.

Passivation

25. Passivation of semiconductor

wafer by forming a layer of an

insulating oxide on the surface

oxide passivation

26. In monolithic ICs, electrical

isolation between devices on the

same substrate is achieved by

fabricating them in an electrically

isolated region known as

isolation pockets or tubs.

27. Which of the isolation techniques

in IC fabrication that is commonly

used? Junction isolation

28. Isolation of devices in integrated

circuit by forming a silicon oxide

layer around each devices is

known as oxide insulation, and

this is a good example of

dielectric isolation

29. An operational amplifier must

have at least how many usable

terminals? 14 terminals

30. What type of amplifier commonly

used at the output stage of op-

amps? Complementary

amplifier

31. the transistor configuration used

at the output complementary

stage of most op-amps common-

collector

32. the stage followed by the output

complementary in op-amps

functional block diagram level

shifter

33. what is the purpose of a level

shifter in op-amps? To set

and/or adjust the output

voltage to zero when input

signal is zero.

34. Primarily, op-amps are operated

with bipolar power supply,

however, we can also use single

polarity power supply by

generating a reference voltage

to ground.

35. Calculate the CMRR of an op-

amp having a common-mode

gain of 10 and a differential-mode

gain of 100,000. 80

36. The non-inverting and inverting

inputs of an op-amp have an

input voltage of 1.5mV and

1.0mV, respectively. If the op-

amp has a common-mode

voltage gain of 10 and a

differential mode gain of 10000,

what is its output voltage?

5.0125V

37. What is the maximum output

voltage swing of an op-amp?

+Vsat to –Vsat

38. The uA741 op-amp has a CMRR

of 90dB and a differential-mode

gain voltage amplification of

200,000. What is the op-amp’s

common-mode voltage gain?

6.324

39. The current needed at the input

of an op-amp to operate it

normally input bias current

40. Ideal op-amp requires no input

current, but real op-amp needs a

very small input current called

input bias current. At both inputs,

the bias currents have a slight

difference. What do you call this

difference? Input offset current

41. the change in input offset current

due to temperature change input

offset current drift

42. the reason why a slight difference

between the input bias current

occurs in op-amps is due to the

unsymmetrical circuit component

parameters. This unsymmetrical

condition also produces a

difference in input voltage called

what? Input threshold voltage

43. ideally, the output voltage of an

op-amp is zero when there is no

input signal, however, in practical

circuits, a small output voltage

appears, this voltage is known as

output offset voltage

44. calculate the output offset voltage

of an inverting amplifier using op-

amp with an input offset current

of 10nA. the current is having an

input resistance of 10k-ohm and

a feedback resistance of 100k-

ohm. 1.0mV

45. an op-amp inverting amplifier

uses a feedback resistor of 100k-

ohm and input resistor of 10k-

ohm. If the op-amps input offset

voltage is 2.0mV, approximate

the amplifier output offset voltage

due to this input offset voltage.

22mV

46. the output offset voltage of an op-

amp is due to the input offset

current and voltage. If 1mV is due

to the input offset current and

22mV due to the input offset

voltage, what is the total output

offset voltage of the op-amp?

23mV

47. how will you minimize the output

offset voltage due to the input

offset current of an op-amp? By

installing a bias-current-

compensating resistor

48. the approximate value of the

bias-current compensating

resistor in op-amp circuits is:

equal to the parallel

combination of the input and

feedback resistors

49. in op-amp analysis, the input

offset voltage is represented by a

battery

50. what is the effect of the input

offset voltage to the output

voltage if the op-amp has no

feedback element? Causes the

output to saturate either towards

positive or negative.

51. How can we minimize the effect

of the input offset current and

input offset voltage at the output

offset voltage? By making the

feedback resistance small

52. An op-amp is wired as an

inverting amplifier with an input

and feedback resistances of 1k-

ohm and 100k-ohm respectively.

When the input signal is set to

zero, the output was found to

have an offset voltage of 101mV.

Calculate the input offset voltage.

1.0mV

53. What is the most effective way of

minimizing the output offset

voltage of an op-amp? By

properly using and adjusting

the offset-null terminals

54. In large signal dc-amplifiers using

op-amp, which parameter has the

least effect on its performance?

Drift

55. For ac-amplifiers using op-amps

what parameters can affect its

performance. Slew rate and

frequency response

56. If an op-amp is used to amplify

small ac-signals, what parameter

should you greatly consider to

ensure better performance?

Frequency response

57. What do we mean by internally

compensated op-amps? op-amps

with internal frequency

compensation capacitor to

prevent oscillation

58. The frequency at which the open-

loop gain of an op-amp is 0.707

times its value at very low

frequency. Break frequency

59. The reduction of op-amps gain

due to increasing operating

frequency. Roll-off

60. Frequency at which the voltage

gain of op-amp reduces to unity.

Unity-gain bandwidth product

61. An op-amp has a specified

transient response rise time of

0.3us, calculate its unity-gain

bandwidth. 1.167MHz

62. What is the maximum signal

frequency that can be used in an

op-amp having a specified slew

rate of 0.5v/usec? The maximum

output voltage desired is 5V.

16kHz.

63. What must be the slew rate of an

op-amp to be used in order to

provide an undistorted output

voltage of 10V at a frequency of

100,000 rad/sec. 1.0V/usec

64. An op-amp zero crossing

detector without hysteresis.

Has no feedback.

65. What is the noise gain of op-

amps? 1+Rf/Ri

66. In most ac-amplifiers using op-

amps, the feedback resistor is

shunted with a very small

capacitance, what is its purpose?

To minimize high-frequency

noise

67. Approximate the noise-gain of an

inverting adder using op-amps if

it has five inputs six(6)

68. What is true about the external

frequency-compensation

capacitor? The lower its value,

the wider its bandwidth.

69. Typical value of the external

frequency-compensating

capacitor of op-amps. 3.0-30 uF

70. The magnitude of the op-amps

input offset voltage before it can

be classified as a low-input offset

voltage op-amp. 0.2mV.

71. Op-amps whose internal

transistor biasing can be

controlled externally are

categorized as programmable-

op-amps

72. The most popular op-amp

packages are the metal can, 8-

pin DIP, and the SMT. Which of

these corresponds to TO-99?

Metal can

73. Dual-in-line or DIL package is

designated as TO-116

74. For high-density ICs, involving

many op-amps, what packaging

is most suitable? SMT

75. A reactive device used in

controlling electrical power by

using two windings on a common

iron core. The control winding is

supplied with small dc-current

which causes the reactance of a

large ac-winding to change

accordingly. Saturable reactor

76. a saturable reactor with

regenerative feedback. Magnetic

amplifier

77. an electronic switch that has the

highest single-device current

capacity and can withstand

overloads better. ignitrons

78. which power control switching

method that greatly generates

RFI or EMI and is therefore

limited to low-frequency

applications? Phase-control

79. a converter that changes ac-

voltage frequency from one to

another. Cycloconverter

80. in electronic converters,

what signal is mostly

used to trigger the active device?

Square wave

81. which of the trigger diodes has

the highest-holding voltage?

Bidirectional-trigger diac

82. general term of electronic devices

used to control or trigger large-

power switching devices. Break-

over devices

83. a break-over device that is

basically a diode. Trigger diode

84. the voltage decreased across the

Anode (A) and cathode (K) of an

SCR from non-conducting state

to conducting state. Breakback

voltage.

85. An SCR rated 10A is used in the

controlling switch in a circuit

powered by 50 Vdc. When the

SCR fires ON, its Anode (A) to

Cathode (K) voltage was

observed to be 2V. Calculate the

breakback voltage of the SCR.

86. Use of heat sinks, forced air, and

water cooling are examples of

external cooling in SCRs and

other devices. Which of these is

the only recommended to be

used for the largest power

dissipating device? Water

cooling

87. In connecting two SCRs in series,

during “OFF” state, the voltage

source must be properly shared

between them, but due to

devices’ differences, there might

be unequal voltages across each

SCR. How do we equalize these

voltages? By using a blocking-

equalizing resistor

88. A circuit used for voltage

equalization during ON-OFF

switching action of SCRs in

series. Snubber circuit

89. in controlling electrical power

using phase control method with

SCR/triac being the active

device, what do we call the

period of the cycle before the

device switches to conduction?

Firing delay angle

90. how many times per second does

an SCR is turned ON and OFF

when it is operated in a full-wave

phase control at a line frequency

of 60 Hz? 120 times (FW)

91. a three terminal device that

behaves roughly like SCRs,

except that it can conduct current

in either direction when at ON.

SBS

92. a thyristor that is very similar to

an SCR except that it has a low

voltage and current ratings. It is

very temperature stable, and is

therefore suitable to be used as a

triggering device. SUS

93. silicon unilateral switches (SUS),

generally have a breakover

voltage of 8V, however, this value

can be altered by normally

connecting a zener diode. How is

the diode installed? Diode’s

cathode to SUS’s gate and

diode’s anode to SUS’s

cathode

94. a silicon unilateral switch (SUS)

has a forward breakover voltage

of 8V. a zener diode is connected

between its gate and cathode

terminals with the diode’s

cathode at SUS’s gate. If the

zener voltage is 3.9V, what is the

new forward breakover voltage of

the device? 4.50V

95. relate the magnitude of the dc-

output voltage to the ac input rms

voltage of a full-wave rectifier.

Vdc=0.90Vrms

96. determine the dc-voltage of a full-

wave bridge rectifier when the

input ac-voltage is 24Vrms. 21.6V

97. ripple factor of a full-wave

rectifier. 0.48

98. A 20V-dc power supply was

found to have a ripple voltage of

2Vrms when supplying 1.5amps

load. Calculate its percent ripple.

10.0%

99. Which power supply filter gives

the smallest ripple voltage?

Multi-section LC-filter

100. Which regulator is the most

inefficient? Shunt

101. Sampling circuit used in most

voltage regulators. Voltage-

divider network

102. a 12Vdc power supply is

regulated using 7805IC and is

used in TTL circuits that require a

0.2 amps current. Determine the

dropout voltage of the system. 7V

103. a load draws 1A current from a

10-V regulated power supply.

Calculate the power dissipated by

the regulator if it has an input

voltage of 16V. 6 watts

104. what three-terminal IC regulator

that has a variable negative

voltage output? 337

105. in a three-terminal adjustable

positive voltage regulator (317),

what is the bandgap voltage

between the output terminal and

adjustment terminal? 1.25V

106. typical ripple rejection of most

three-terminal voltage regulators.

0.1%

107. the three-terminal voltage

regulators, such as the 78xx

series has a typical current rating

of 1.5 amperes. If a high current

is required, say 30 amperes, how

will you make modifications for

this regulator in order to provide

the required current? By the use

of external pass transistor

108. active devices used in switching

regulators may experience large

over-currents during conduction

(turn-on-state) and large over-

voltages during turn-off. These

excessive currents and voltages

may cause distraction or damage

of the active devices. How do we

protect them? By installing a

snubber circuit.

109. In switching SCRs to on-state,

the current rises rapidly and

some-times causes damage to

the device. One way of

preventing this to happen is by

connecting an inductance in

series with the load. If for

example, an SCR with a di/dt

rating of 100A/us and is used in

220 Vac, what should be the

value of the inductance to be

used? 2.48uH

110. When SCRs switches to “off”

from on-state, a voltage across

the anode and cathode rises

rapidly, this voltage change

creates a voltage gradient

internally and may cause the

SCR to trigger again. To prevent

this unscheduled firing, a

capacitor may be installed across

the SCR. For an SCR with a

maximum forward-blocking

voltage of VFBM=500V and a

maximum dv/dt of

25V/us,calculate the capacitance

needed to prevent unscheduled

firing if the SCR has a load of 10-

ohm. 2uF

111. One of the major concerns in

power electronics is to clean-up

or shape-up the utility-supply

voltage (the wall outlet

220V/60Hz) from disturbances

such as overvolt, undervolt,

voltage spikes and harmonic

distortions. What circuit is used

for this? Power conditioners

112. Karnaugh map is the most

commonly used method in

simplifying Boolean expression or

logical functions. In this method

only 1’s and 0’s are entered into

the table, while map-entered

variable technique includes

variable into the table.

113. A suitable method in simplifying

Boolean expression when the

system deals with more than six

variables. Quine-mccluskey

tabular method

114. If the fan out of a logic gate is not

enough, a/an buffer should be

used.

115. Is considered as a controller

inverter. XOR

116. Known as universal gates NOR

and NAND

117. The number of NAND-gates

needed to form an OR-gate. 3

118. Flip-flop that changes state every

time the input is triggered.

Master slave flip-flop

119. Type of memory that is formed by

a series of magnetic bubbles at

the substrate bubble memory

120. Digital device similar to that of a

ROM and whose internal

connections of logic arrays can

be programmed by passing high

current through fusable links.

PLA and PAL

121. A circuit used for selecting a

single output from multiple inputs

universal logic module (ULM)

122. What is formed when the

complemented output of the last

stage of a shift register is fed

back to the input of the first

stage? Twisted ring counter

123. Refers to the ability of a logic

circuit to withstand noise

superimposed on its input signal.

Noise immunity

124. The number of logic gates of the

same family that can be

connected to the input of a

particular gate without degrading

the circuit performance. Fan-in

125. A logic circuit family with a supply

voltage of 25V. and are generally

used in industry where machinery

causes electrical noise and large

power line transients to

occur.HLDTL

126. in a transistor-transistor-logic

(TTL), if the base collector

junction of a transistor is clamped

with a Schottky-diode it becomes

Schottky TTL. What is the

significance of having this diode?

It increases the switching

speed

127. PMOS are generally supplied

with a voltage up to 15 V

128. NMOS can be interlaced to

CMOS by providing a pull-up

resistor

129. a digital IC whose output

transistor has no internal pull-up

resistor. Open-collector

configuration

130. in digital ICs, such as buffers and

registers, what output

configuration is used if they are

intended for “busing” ? tri-state

output

131. in TTL ICs, which input

configurations gives a high-input

impedance at both logic states

(HIGH and LOW state)?

Substrate pnp input

132. what is the purpose of internal

clamping diodes at the input of a

logic circuit? To minimize

negative ringing effects

133. in TTL ICs with more than one

gates available, sometimes not

all gates are used. How will you

handle these unused gates?

Force the output to go HIGH

134. how will you handle unused

inputs in a logic gate/logic IC?

Pull them up or down,

depending on circuit function

INSTRUMENTATION/ ENERGY

CONVERSION/ OTHERS

1. An instrument which depends on

current in one or more fixed coils acting on one or more pieces of soft iron, at least one of which is movable.

moving-iron instrument

2. What is that device which depends on the action of a movable permanent

magnet in aligning itself in the resultant field produced either by a fixed permanent magnet and an

adjacent coil or coils carrying current or by two or more current-carrying coils whose axes are displaced by a

fixed angle? moving-magnet instrument

3. What ammeter is mostly used in

measuring high-frequency currents? thermocouple

4. This instrument measures

temperatures by electric means, especially temperatures beyond the range of mercury thermometers.

pyrometer

5. This instrument refers to that one which measures the intensity of the

radiation received from any portion of the sky pyranometer

6. A device used to mechanically measure the output power of a motor. dynamometer

7. An indicating instrument whose movable coils rotate between two stationary coils, usually used as

wattmeter. electrodynamometer

8. Error in ohmmeter reading is due to

battery aging

9. Which of the ammeter below that has no insertion error?

clamp-meter

10. To prevent damage of the multirange ammeter during selection, a/an

_________ should be used. Ayrton shunt

11. Voltage measurement in a high

impedance circuit requires a voltmeter

with high input impedance

12. If a meter with a full-scale current of 100uA is used as an ac voltmeter with half-wave rectification, its ac sensitivity

is 4,500 Ω/V

13. The zero-adjust control in an analog

type ohmmeter is used to compensate for the differing internal battery voltage

14. Dynamometers are mostly used as wattmeter

15. What damping method is generally

used in dynamometers? air friction

16. Which dynamometer instrument has a

uniform scale? wattmeter

17. For a dynamometer to be able to

measure high current, a ___ should be used. current transformer

18. The scale of a hot wire instrument is a/an ________ function. squared

19. Moving iron instruments have a scale function that is squared

20. To increase the measuring capability of a moving-iron ac meter, a ____ should be used.

different number of turns of operating coil

21. Which electrical instruments below is

the most sensitive? PMMC

22. Controlling torque in PMMC.

spring action

23. What damping method is used in induction type ammeters?

electrostatic damping

24. Induction type instruments are mostly used as

watt-hour meter

25. The force(s) that is(are) acting on the pointer of an indicating instrument as

they rest on there final deflected position. (Note: damping torque is 0). controlling & deflecting torques

26. What is (are) the force(s) acting on the pointer of an indicating instrument when it is in motion? controlling, damping, and defecting

torques

27. A Kelvin electrostatic voltmeter uses what method of damping?

fluid friction

28. In a moving coil ammeter, a ________ is connected in series with the coil to

compensate for temperature variations. swamping resistor

29. What is this measuring instrument that uses the force of repulsion between fixed and movable magnetized iron

vanes, or the force between a coil and a pivoted vane-shaped piece of soft iron to move the indicating pointer?

vane-type instrument

30. Its an electrostatic voltmeter in which an assembly of figure – 8 – shaped

metal plates rotates between the plates of a stationary assembly when a voltage is applied between the

assemblies. The length of the arc of rotation is proportional to the electrostatic attraction and thus, to the

applied voltage. Kelvin voltmeter

31. What is that instrument used for

measuring the strength and direction of magnetic fields? magnetometer

32. What do you call of that instrument used for measuring reactive power vars?

either varmeter or reactive volt-ampere meter

33. This is a method of using a

Wheatstone bridge to determine the distance from the test point to a fault in telephone or telegraph line or cable.

Varley loop

34. This refers to a four-arm ac bridge used for measuring inductance against

a standard capacitance. Maxwell bridge

35. Refers to an ac bridge for measuring

the inductance and Q of an inductor in terms of resistance, frequency and a standard capacitance.

Hay bridge

36. This is a special bridge for measuring very low resistance (0.1Ω or less).

The arrangement of the bridge reduces the effects of contact resistance which causes significant error when such low resistances are

connected to conventional resistance bridges. Kelvin double bridge

37. A type of four-arm capacitance bridge in which the unknown capacitance is compared with a standard

capacitance. This bridge is frequently employed testing electrolytic capacitors, to which a dc polarizing

voltage is applied during the

measurement. What is this bridge? Schering bridge

38. What do you call of that frequency-sensitive bridge in which two adjacent arms are resistances and the other

two arms are RC combinations? Wein bridge

39. When the capacitors of a Wein bridge

are replaced by inductors, the bridge becomes Wein inductance bridge

40. A simplified version of the Wheatstone bridge wherein, two of the ratio arms are replaced by a 100 cm long

Manganin of uniform cross-sections and provided with a slider. slide-wire bridge

41. Electrical machine that converts ac voltage to dc voltage, or vice versa. rotary converter

42. Electrical machine that changes ac voltage at one frequency to another ac voltage at another frequency.

frequency converter

43. A Synchronous type ac-motor, uses a dc – generator to supply dc

– excitation to the rotating field

44. In a compound generator, which field winding usually, has a lower

resistance? series field winding

45. Which winding in a dc-compound

generator that is relatively made of fine wires? shunt field winding

46. What is the primary reason why carbon brushes are preferred over copper brushes in dc motors?

they product less arcing

47. To minimize arcing during starting of dc motors, a resistance should be

added to limit the current in the ____ armature winding

48. Motors whose speed can be easily

controlled. dc motors

49. When a dc motor has no load, what

will happen to the back emf? becomes maximum

50. When can we get a maximum

mechanical power from a dc motor? Eb = 0.5V

51. One cause why the shaft torque is less than the developed armature torque of

a dc motor. friction loss

52. Considered as a variable speed motor

series

53. What is the most common method used in varying the sped of a dc

motor? by varying the field strength

54. In choosing a motor for a particular

application, what characteristic you should consider? speed-torque

55. A motor whose speed increases as the load is increased. differentially compounded

56. Factor(s) that affect iron losses in a dc motor. flux & fied are correct

57. One advantage of a cumulatively compounded motor is that it does not run widely at light loads, this feature is

due to shunt winding

58. In applications where an almost

constant speed is required, a ______ motor is a good choice. dc shunt

59. In applications where a high torque is needed during starting, a ______ motor is preferred.

dc series

60. In applications where sudden heavy loads happen for short duration, a

______ motor is the best choice. cumulatively compounded

61. In motors of the same rating, which

has the least starting torque? dc shunt

62. Factor(s) that affect friction and

winding loses in dc motors. speed

63. In dc motors, power loss is contributed

greatly by copper loss

64. When a motor is overloaded, it will

usually overheat

65. Which motor that produces the highest

increase in torque considering the same increase in current? dc series

66. When an armature opens in dc motor, it may cause intermittent sparking

67. Why do motors take large current during starting? there’s still a low back emf

68. The law which pertains, for any

dielectric reflector, the relationship in which the reflective index is equal to the tangent of the polarizing angle.

Brewster’s angle

69. A law that states the current in a thermoionic diode varies directly with

the three-halves power of anode voltage and inversely with the square of the distance between the

electrodes, providing operating conditions are such that the current is limited only by the spacecharge.

Child’s law

70. The logarithm of the decay constant of an alpha emitter is linearly related to

the logarithm of the range of the alpha particles emitted by it is called _____. Geiger-Nuttal law

71. The law that processing power of a computer is proportional to the square of its cost.

Grosh’s law

72. The law which states an electric motor develops maximum power when Ei =

2Ebk, where Ei is the applied voltage an dEbk is the back-emf. Jacob’s law

73. The law which refers to the strength of the magnetic field at a given point, due to an element of a current-carrying

conductor, is directly proportional to the strength of the current and the projected length of the element and

inversely proportional to the square of the distance of the element from the point in question.

Laplace’s law

74. The law which concerns to a property of mutual inductances. For a given

orientation and environment for two inductors, the value of the mutual inductance does not change,

regardless of the magnitude, frequency, or phase of the currents in the coils. That is, mutual inductance is

subject only to the physical environment surrounding the coils. Neumans law

75. The law that sparkling potential between two parallel place electrodes in a gas I a function of the product of

the gas density and the distance between the electrodes. either Paschen’s rule or Paschen’s

law is right

76. The rule that hysteresis loss in a magnetic material varies directly in proportion with the cube of the

magnetic induction. Rayleigh’s law

77. The thermal-radiation law that shows

the total emissive power of ablackbody to be proportional to the fourth power of the absolute temperature of the

body. Stefan-Boltzmann law

78. The wavelength of luminescence

excited by radiation is always greater than that of the exciting radiation. Stoke’s law

79. It is a law expressing the relationship nbetween a stimulus and the

physiological reaction ir produces: The sensation is proportional to the logarithm of the stimulus

Weber-Fechner law

80. The law indicating that the wavelength of maximum radiation of a blackbody

is inversely proportional to the absolute temperature. either Wien’s first law or Wien’s

displacement law

81. The law showing that the emissive power of a black body is proportional

to the fifth power of absolute temperature is known as either Wien’s radiation law or

Wien’s second law

82. It is an empirical law for the spectral distribution of energy radiated from a

black body at a specified temperatre. Wien’s third law

83. An electromagnetic wave will take a

path that involves the least travel time when propagating between two points. Fermat’s principle

84. The rule that states, during transitions of orbital electrons from higher to lower energy states (accompanied by

the emission of the photons), changes in the inner quantum number may not only e by a factor of 0 r +/- 1.

J rule

85. This is an extension of the two-fluid model of superconductivity, in which it

is assumed that superfluid electrons behave as if the only force acting on them arises from the applied electric

fields, and that the curl of the superfluid current vanishes in the absence of a magnetic field.

London superconductivity theory

86. A formula for the overall transmittance of a signal flow graph in terms of

transmittances of various paths in the graph. Mason’s theorem

87. This applied to a nonradiative transition of an tom from an excited energy state to a lower energy state,

accompanied by the emission of an electron Auger effect

88. Refers to the selective absorption of

electromagnetic waves by a dielectric, due to molecular dipoles Dobye effect

89. The rotation induced in a freely suspended ferromagnetic object when magnetization of the object is

reversed. Einstein-de Has effect

90. The random variations in the output current of an electron tube that has an

oxide-coated cathode, caused by random changes in cathode emission. flicker effect

91. What do you call of the momentary illumination produced when an electric field is applied to a phosphor

previously excited by ultraviolet radiation? Gudden-Pohl effect

92. The ability of ultraviolet radiation to discharge a negatively charged body in a vacuum.

Hallwachs effect

93. The phenomenon whereby current in a gas changes as the result of irradiation

by light is called Joshi effect

94. The variation (caused by the earth’s

magnetic field) of the strength of cosmic rays arriving at different longitudes on the surface of the earth

is known as longitude effect

95. This is the effect when the

magnetization of a helically wound, ferromagnetic wire fluctuates, the tendency for a potential difference to

occur. Mateucci effect

96. _______ refers to the scattering of

monochromatic light (light of a single wavelength) when passed through a transparent substance.

Raman effect

97. This is the ability of an electric current to destroy superconductivity by the

magnetic field that it generates, without raising the cryogenic temperature.

Silsbee effect

98. Electric polarization of a dielectric material being moved in a magnetic

field. Wilson effect

99. What is the two-terminal semi-

conductor device which resembles the behavior of a neuron and allows machines to duplicate some of the

neurological phenomena observed in the human body? neuristor

100. What gadget that electronically aids

the blind which has a camera that scan printed matter and a device forms corresponding raised letters

which can be read with the fingertips? optacon

101. What do you call of a monostable

pentode circuit that generates sharp pulses at an adjustable and accurately timed interval after receipt of a

triggering signal? phantastron

102. What instrument is used to measure the intensity of radiation, such as by determining the amount of

fluorescence produced by that radiation? actinometer

103. _________ referred to a visual sensation experienced by a human subject during the passage of current

through the eye. phosphene

104. It is a pattern that consists of pairs of

white an dark parallel lines, obtained when an electron beam is scattered (diffracted) by a crystalline solid. The

pattern gives information on the structure of the crystal. Kikuchi lines

105. An operational amplifier with double feedback limiters that drive a high-speed relay (1-2 milliseconds) is an

analog computer, usually involved in controlled programming. bang-bang circuit

106. The arrangement of connecting wires in a circuit to prevent undesirable coupling and feedback.

dress

107. What is that device used in biotelemetry for monitoring physiologic

activity of an animal, such as pH values of stomach acid? radio pill

108. Refers to noise produced by erratic jumps of bias current between two levels at random intervals in

operational amplifiers and either semiconductor devices. popcorn noise

109. A conductor in which two oscillating circuits have the same resonant frequency is called

systony

110. Refers to triode electron tube having an anode that can be moved or

vibrated by an externally supplied force. vibrotron